These timers will provide periods of up to 24-hours and way beyond. Build them yourself using stripboard or veroboard - and a few cheap off-the-shelf components.
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Simulation

Circuit Description

To see the difference between the two circuits move the mouse pointer over the schematic. In the first circuit - the NPN transistor switches the negative side of the coil. In the second circuit - the PNP transistor switches the positive side of the coil. The two circuits are otherwise identical. In what follows - I've concentrated on describing Timer No.1. However - where appropriate - I've included an account of how Timer No.2 differs.
Breadboard No.1 Test Procedure Breadboard No.2
Image Effect Courtesy Of DynamicDrive.Com

Construction Guide

Circuit No.1





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Construction Notes

Click here if you're new to constructing stripboard projects.

The terminals are a good set of reference points. To fit them - you may need to enlarge the holes slightly. Then turn the board over and use a felt-tip pen to mark the 21 places where the tracks are to be cut. Before you cut the tracks, use the "actual size" drawing to Check That The Pattern is Correctly Marked .

Actual Size





When you're satisfied that the pattern is right - cut the tracks. Make sure that the copper is cut all the way through. Sometimes a small strand of copper remains at the side of the cut and this will cause malfunction. Use a magnifying glass - and backlight the board. It only takes the smallest strand of copper to cause a problem. If you don't have the proper track-cutting tool - a 6 to 8 mm drill-bit will do. Just use the drill-bit as a hand tool - there's no need for a drilling machine.




Next make and fit the Five Wire Links. I used bare copper wire on the component side of the board. Telephone cable is suitable - the single stranded variety used indoors to wire telephone sockets. Stretching the core slightly will straighten it - and also allow the insulation to slip off.

Then fit the six resistors and the preset. The resistors are all shown lying flat on the board. But those connected between close or adjacent tracks are actually mounted standing upright. See The Photo Of The Prototype .

Now fit the transistor - the two diodes - the IC socket - and the relay. Pay particular attention to the orientation of the diodes. Note that both are facing in the same direction. Again - both diodes are shown lying flat on the board - but D2 is actually mounted standing upright.



Next, fit the remaining components - the 3 capacitors and 2 LEDs. Then examine the underside of the board carefully; to make sure that there are no unwanted solder bridges or other connections between the tracks. If you backlight the board during the examination - it makes potential problem areas easier to spot.

When you're satisfied that everything is in order - add the five solder bridges to the underside of the board. These are just small blobs of solder. I've used them to connect adjacent tracks. They are a simple and convenient alternative to wire links.

Finally - insert the Cmos 4060 into the socket. Make sure that pin 1 is in the top left-hand corner - and check very carefully that all of the pins are correctly inserted into the socket. Sometimes - instead of entering the socket - a pin will curl up underneath the IC.

You Are Now Ready To Test Your Timer


Construction Guide

Circuit No.2




The terminals are a good set of reference points. To fit them - you may need to enlarge the holes slightly. Then turn the board over and use a felt-tip pen to mark the 21 places where the tracks are to be cut. Before you cut the tracks, use the "actual size" drawing to Check That The Pattern is Correctly Marked .

Actual Size





When you're satisfied that the pattern is right - cut the tracks. Make sure that the copper is cut all the way through. Sometimes a small strand of copper remains at the side of the cut and this will cause malfunction. Use a magnifying glass - and backlight the board. It only takes the smallest strand of copper to cause a problem. If you don't have the proper track-cutting tool - a 6 to 8 mm drill-bit will do. Just use the drill-bit as a hand tool - there's no need for a drilling machine.




Next make and fit the Five Wire Links. I used bare copper wire on the component side of the board. Telephone cable is suitable - the single stranded variety used indoors to wire telephone sockets. Stretching the core slightly will straighten it - and also allow the insulation to slip off.

Then fit the six resistors and the preset. The resistors are all shown lying flat on the board. But those connected between close or adjacent tracks are actually mounted standing upright. See The Photo Of The Prototype .

Now fit the transistor - the two diodes - the IC socket - and the relay. Pay particular attention to the orientation of the diodes. Note that both are facing in the same direction.



Next, fit the remaining components - the 3 capacitors and 2 LEDs. Then examine the underside of the board carefully; to make sure that there are no unwanted solder bridges or other connections between the tracks. If you backlight the board during the examination - it makes potential problem areas easier to spot.

When you're satisfied that everything is in order - add the four solder bridges to the underside of the board. These are just small blobs of solder. I've used them to connect adjacent tracks. They are a simple and convenient alternative to wire links.

Finally - insert the Cmos 4060 into the socket. Make sure that pin 1 is in the top left-hand corner - and check very carefully that all of the pins are correctly inserted into the socket. Sometimes - instead of entering the socket - a pin will curl up underneath the IC.

You Are Now Ready To Test Your Timer


General Information


Do not use the "on-board" relays to switch mains voltage. The board layouts do not offer sufficient isolation between the relay contacts and the low-voltage components. If you want to switch mains voltage - mount a suitably rated relay somewhere safe - Away From The Board.